1. Field of the Invention
The present invention generally relates to a fluxgate sensor and a fabrication method thereof. More particularly, the present invention relates to a fluxgate sensor using a CoNbZr magnetic core, and a fabrication method thereof.
2. Description of the Related Art
A fluxgate sensor can detect magnetic energy that is insensible directly by human sensory organs. Such a magnetism sensor has a broad application in various fields such as airplanes, location awareness systems for ship and vehicle, motion detection in virtual space, terrestrial magnetism compensation and bleeding color correction of HDTV, and magnetoencephalography and magnetocardiography using medical instruments.
A micro fluxgate sensor is mainly composed of a magnetic core which is wound with two coils. One coil, an excitation coil, is used to produce a magnetic field which saturates the magnetic core. The other coil, a detection coil or a magnetic field sensing coil, is used to detect changes in the magnetic flux in the core. A basic sensing principle of a fluxgate sensor lies in a non-linear characteristic, i.e., saturation characteristic of the magnetic core. When a magnetic field is generated by supplying sufficient alternating current to the excitation coil, magnetic flux density in the magnetic core is saturated periodically. At this time, when an external magnetic field, which is to be measured, is applied, the magnetic flux density in the magnetic core changes and the magnetic field sensing coil measures intensity of the external magnetic field by measuring the change of the magnetic flux density in the core.
Coercivity is the intensity of the applied magnetic field required to reduce the magnetization of a magentic material to zero after the magnetization of the material has been driven to saturation. For a fluxgate sensor, it is advantageous to have a low cocercivity. Permalloy has been used as a material of a core of fluxgate sensors because it has a high magnetic permeability and low coercivity. The permalloy refers to a nickel iron magnetic alloy such as Fe—Ni alloy, Fe—Ni—Mo alloy, and the like.